Conventional electrical connectors include a housing formed of a blade holder and a retainer attached by at least one fastener. A blade contact is resiliently coupled to the blade holder and extends through a contact opening in the blade holder such that its blade end extends exteriorly of the housing. A wire connection end of the contact is located in an inner cavity formed between the blade holder and retainer.
An externally threaded screw is rotatably coupled to the wire connection end of the blade contact, and is restrained against axial movement by the retainer and the contact. A wire clamp threadedly mounted on the screw moves toward and away from the contact connection end upon rotation of the screw.
A relatively light resilient connection is provided between the blade holder of the housing and the blade contact to facilitate insertion of the contact in the blade holder. The resilient connection is in the form of a snap connection formed by merely inserting the blade within the opening. Ease of insertion and positive locking of the blade contact in the blade holder is necessary for mass production of the electrical connector.
Recent federal specifications require that the distance the blade contact extends from the face of the electrical connector plug must be maintained, even after a high mechanical load is applied to reduce that distance, i.e., tending to push the blade contact back into the housing. The form of the blade contact is fixed by N.E.M.A. standards, while the wire termination arrangement is determined primarily by U.L. requirements for "dead-front" construction.
The metal contacts for the connectors are made from ductile alloys with insufficient rigidity to withstand the high mechanical loads required by the specifications, without an unacceptable degree of deformation. Increasing the rigidity of the resilient connection between the blade contact and the blade holder adversely affects the manufacture of the electrical connector by making it more difficult to insert the blade contact within the blade holder. Thus, an electrical connector is needed wherein the blade contact and its connection to the blade holder are substantially unchanged, while providing sufficient rigidity to the device to permit the connector to withstand the application of high mechanical loads on the blade contact in a direction towards its housing.